being a trek, you might be swap out your current handlebar and grips for the isozone handlebar & grip system without much hassle. wasn't a feature that even crossed my mind when buying an fx, but after riding it for a while i cannot believe how comfortable it is. seems super gimmicky, but in my opinion it's a gimmick that works.
$70 for the bar and grips on trek's website:
https://www.trekbikes.com/us/en_US/e...olorCode=black
my hands used to go numb on long rides. that problem went away on its own. way before the fx. no idea what changed or if i changed anything, but it's not a problem anymore. i still ride the same bike as when it was a problem, the jamis ventura race. so whatever changed wasn't equipment related. back when it was a problem, gloves certainly didn't help me either.
hope you get it figured out. no idea if it'd help, but i can attest that the isozone system is a pleasure.